During the fabrication of the semiconductor device, after the desired photoresist mask is formed, the wiring pattern is formed by etching. Then the unnecessary resist layer, including the resist layer on top of the wiring pattern, is removed with the resist removal solution and cleaned with a rinse solution. Then it is necessary to use a rinsing process called water washing.
In such cases, as for the solution used to remove the resist, acidic or alkaline removal solutions can be named. As the representative of the acidic resist removal solution, the removal solutions obtained by mixing alkylbenzenesulfonic acid with phenol compounds, chlorinated solvents and aromatic hydrocarbons are sold commercially and used widely but, although such conventional solutions remove resists excellently, they have the problem of generating pit-shaped corrosion caused by alkylbenzenesulfonic acid on the surface of Al-Si-Cu wiring, which is widely used in high-density integrated circuits. In addition, the fact they contain phenol compounds, which are highly toxic, and chlorinated compounds, which can cause environmental pollution, presents a problems. Also, as for alkaline resist removal solution, the removal solutions composed of organic alkali and all kinds of organic solvents are sold commercially and used widely. Since these alkaline resist removal solutions have low toxicity and little effect on environmental pollution, they have been used extensively in recent years. However, although alkaline resist removal solutions exhibit the same excellent resist removal property as the above-mentioned acidic resist removal solutions, they have the problem of pitting the surface of the Al-Si-Cu wiring material by the alkaline component. This problem remains to be solved.
In order to solve the problem of generating pitting on the surface of the Al-Si-Cu wiring material by removing the resist with an alkaline solution, it has been determined, in accordance with the invention, that the this kind of corrosion is caused by the dissociation of alkaline components mixed into the rinse solution from the alkaline resist removal solution which is mixed in during the water rinse process carried out as the last removal process.